FDA Approves Moderna’s mRNA Flu Vaccine for Adults 50 and Older

The Food and Drug Administration has cleared mFlusiva, a groundbreaking influenza vaccine developed by Moderna using mRNA technology, marking the first flu shot of its kind to reach the U.S. market. The vaccine is designed for adults age 50 and above, with the Cambridge, Massachusetts-based pharmaceutical company announcing late Wednesday that initial supplies should arrive at select retail locations imminently as flu season approaches.

Moderna received full FDA approval for use in people between ages 50 and 64 following clinical data from 40,000 participants demonstrating approximately 27 percent efficacy compared to a standard flu vaccine. For individuals 65 and older, the company obtained accelerated approval status contingent on findings from a smaller trial showing robust immune response relative to existing high-dose senior vaccines, pending completion of an additional postmarketing study.

The mRNA platform enables manufacturers to produce vaccines substantially faster than conventional methods, a capability experts believe could prove vital should the flu virus undergo significant mutations requiring rapid vaccine reformulation. Annual flu vaccination updates are necessary because the virus continuously evolves, and the U.S. currently has multiple flu vaccine options available, including three variants specifically recommended for seniors.

Clinical data revealed the vaccine produced temporary side effects including injection site soreness, fever, headache, fatigue and muscle aches at slightly elevated rates compared to traditional flu shots, though no serious safety concerns emerged. The approval followed an unusual public disagreement earlier this year when an FDA official initially blocked the application, prompting Moderna to publicly challenge the decision before an independent FDA advisory panel unanimously recommended approval in June.